In laser diodes with a ridge waveguide structure, also known as a ridge, a lateral waveguiding takes place during operation through a refractive index jump between the ridge area and the material adjacent to the ridge, whereby one or more laser modes build up laterally in the active zone, defined inter alia by the ridge. The current injection into the diode, through which the active zone is electrically pumped into inversion, which makes laser operation possible, is effected by contacting the top region of the ridge. The optical mode(s) decays exponentially laterally outside the ridge area, while the current in the ridge is limited by the side walls and can only spread below the ridge due to the transverse electrical conductivity of the material located there. In order to obtain efficient devices with curves that are as linear as possible, however, it is necessary to bring the pumped area and the mode area to overlap as advantageously as possible. However, a change in the dimensions of the ridge always has an influence on the mode behavior and at the same time on the current conduction, which greatly limits the possibilities for optimizing this overlap.
Usually the definition of the ridge defines the mode guidance and the current spreading simultaneously and not independently of each other. There are known construction forms in which the width of the electrical contact on the ridge is varied in order to vary the local current imprint. However, the at least partially inevitably narrower contact area has the disadvantage that the operating voltage increases.